Endothelial Caveolae Have the Molecular Transport Machinery for Vesicle Budding, Docking, and Fusion Including VAMP, NSF, SNAP, Annexins, and GTPases

Purification and properties of a palmitoyl-protein thioesterase that cleaves palmitate from H-Ras.

Two of four proteins that associated with translocation intermediates during protein import across the outer chloroplast envelope membrane were identified as guanosine triphosphate (GTP)-binding proteins. Both proteins are integral membrane proteins of the outer chloroplast membrane, and both are partially exposed on the chloroplast surface where they were accessible to thermolysin digestion. Engagement of the outer membrane's import machinery by an import substrate was inhibited by slowly hydrolyzable or non-hydrolyzable GTP analogs. Thus, these GTP-binding proteins may function in protein import into chloroplasts.

https://science.sciencemag.org/content/sci/266/5187/1035.full.pdf

Identification of two GTP-binding proteins in the chloroplast protein import machinery

Gz, a guanine nucleotide-binding protein with unique biochemical properties.

Identification of a small GTP-binding protein, Rab25, expressed in the gastrointestinal mucosa, kidney, and lung

Membrane proteins from rabbit and human platelets were separated by SDS/polyacrylamide-gel electrophoresis and the resolved polypeptides blotted on nitrocellulose. A family of GTP-binding proteins, termed Gn proteins, was detected by incubation of these blots with [alpha-32P]GTP in the presence of Mg2+. A major Gn protein with a molecular mass of 27 kDa (Gn27) and lesser amounts of 23, 24 and 25 kDa Gn proteins were observed in platelet membranes; much smaller amounts were in the platelet soluble fraction. Binding of [alpha-32P]GTP by platelet Gn proteins was blocked by GDP, GTP or guanosine 5'-[gamma-thio]triphosphate, but not by GMP or adenosine 5'-[beta gamma-imido]triphosphate. Rabbit and human red-cell membranes contained only Gn27. When rat tissues were analysed for Gn proteins, the largest amounts were found in brain, which contained two membrane-bound forms (Gn27 and Gn26) and a soluble form (Gn26).

R P Bhullar

Papers

Detection of 23-27 kDa GTP-binding proteins in platelets and other cells.